This disclosure is generally directed to photoreceptors, photoconductors, and the like. More specifically, the present disclosure is directed to multilayered drum, or flexible belt imaging members, or devices comprised of a first layer, which first layer, in embodiments, is comprised of a glycoluril resin and an acrylic resin, such as a self crosslinking acrylic resin, and also where a catalyst can be included in the resin mixture to assist in crosslinking the mixture components, and where the first layer, in embodiments, is referred to as a backside coating layer or curl deterring backside coating layer (ACBC), and which layer is in contact with and contiguous to the reverse side of the supporting substrate, that is this side of the substrate that is not in contact with the photogenerating layer; a supporting medium like a substrate, a photogenerating layer, and a charge transport layer, including a plurality of charge transport layers, such as a first charge transport layer and a second charge transport layer, an optional adhesive layer, an optional hole blocking or undercoat layer, and an optional overcoat layer, and wherein the supporting substrate is situated between the first layer and the photogenerating layer. More specifically, the photoconductors disclosed in embodiments enable a number of advantages, such as permit acceptable anticurl characteristics in combination with excellent conductivity, prolonged wear, excellent bulk conductivity, acceptable friction coefficient characteristics, for example a lower friction coefficient than a comparable photoconductor that is free of the resin mixture disclosed herein; an ACBC layer with almost 100 percent transmission enabling imaging from the back of the photoconductor; a dispersion formation is avoided which can cause manufacturing difficulties, and non-uniformity; the conductivity of the resin mixture ACBC layer is substantially uniform and reproducible; excellent surface slipperiness, and scratch resistant characteristics; wear resistance properties; and minimal agglomeration of the ACBC mixture components.
While not being desired to be limited by theory, it is believed that the ACBC layer components provide a conductive matrix and permit the transmission of light. The aforementioned transparency of, for example, about 90 to about 100 percent allows for excellent photoreceptor applications since the erase illumination is applied from inside the belt module and passes through the ACBC layer into the photogenerating layer. The electrical conductivity of the ACBC layer allows the triboelectrically generated charges to move through the layer, and discharge before the quantity of charge builds up to significant levels.
In some instances, when a flexible layered photoconductor belt is mounted over a belt support module comprising various supporting rollers and backer bars present in a xerographic imaging apparatus, the anticurl or reduction in curl backside coating (ACBC), functioning under a normal xerographic machine operation condition, is repeatedly subjected to mechanical sliding contact against the apparatus backer bars and the belt support module rollers to thereby adversely impact the ACBC wear characteristics.
Moreover, with a number of known prior art ACBC photoconductor layers the mechanical interactions against the belt support module components can decrease the lifetime of the photoconductor primarily because of wear and degradation after short time periods. Belt modules that incorporate large numbers of sliding positioning supports generate a large amount of electric charge from the sliding contact which needs to be discharged by the costly combination of carbon fiber brush and a bias power supply. Failure to discharge the ACBC produces a large electrostatic attractive force between the photoreceptor and the support element which increases the normal force producing more drag which complicates photoreceptor belt removal, and can become large enough to stall the drive motor. In addition, the multiple points of sliding contact generate a significant quantity of fine polymer dust which coats the machine components and acts as a lubricant, reducing drive roller capacity. Drive capacity is restored by having a technician or a customer devote time to the solvent cleaning all the rollers and backer bars each time a photoreceptor belt is changed. These and other disadvantages are eliminated or minimized with the photoconductors of the present disclosure.
In embodiments, the photoconductors disclosed include an ACBC (anticurl back coating) layer on the reverse side of the supporting substrate of a belt photoreceptor. The ACBC layer, which can be solution coated, for example, as a self-adhesive layer on the reverse side of the substrate of the photoconductor, comprises known glycoluril and acrylic resin mixtures, and where the mixture is crosslinked, and that, for example, substantially reduces surface contact friction, and prevents or minimizes wear/scratch problems for the photoreceptor device. In embodiments, the mechanically robust ACBC layer of the present disclosure usually will not substantially reduce the layer's thickness over extended time periods adversely affecting its anticurl ability for maintaining effective imaging member belt flatness while minimizing the formation of dirt and debris.
Moreover, high surface contact friction of the backside coating against machines, such as xerographic printers, and its subsystems can cause the development of undesirable electrostatic charge buildup. In a number of instances, with devices, such as printers, the electrostatic charge builds up because of high contact friction between the anticurl backside coating and the backer bars which increases the frictional force to the point that it requires higher torque from the driving motor to pull the belt for effective cycling motion. In a full color electrophotographic apparatus using a 10-pitch photoreceptor belt, this electrostatic charge buildup can be high due to the large number of backer bars used in the machine.
The backside coating layers illustrated herein, in embodiments, have excellent wear resistance, extended lifetimes, minimal charge buildup, excellent bulk conductivity, and permit the elimination or minimization of photoconductive imaging member belt ACBC scratches.
Also included within the scope of the present disclosure are methods of imaging and printing with the photoresponsive or photoconductor devices illustrated herein. These methods generally involve the formation of an electrostatic latent image on the imaging member, followed by developing the image with a toner composition comprised, for example, of thermoplastic resin, colorant, such as pigment, charge additive, and surface additive, reference U.S. Pat. Nos. 4,560,635; 4,298,697 and 4,338,390, the disclosures of which are totally incorporated herein by reference, subsequently transferring the toner image to a suitable image receiving substrate, and permanently affixing the image thereto. In those environments wherein the device is to be used in a printing mode, the imaging method involves the same operation with the exception that exposure can be accomplished with a laser device or image bar. More specifically, the flexible photoconductor belts disclosed herein can be selected for the Xerox Corporation iGEN® machines that generate with some versions over 100 copies per minute. Processes of imaging, especially xerographic imaging and printing, including digital and/or color printing, are thus encompassed by the present disclosure. The imaging members are, in embodiments, sensitive in the wavelength region of, for example, from about 400 to about 900 nanometers, and in particular from about 650 to about 850 nanometers, thus diode lasers can be selected as the light source. Moreover, the imaging members of this disclosure are useful in color xerographic applications, particularly high-speed color copying and printing processes.